Thermal energy harvesting system using a thermoelectric generator (TEG) can operate low voltage devices up to 5 V. The TEG will act as a small electric generator from the temperature difference obtained from two different conditions. Soil is an excellent source to get a more considerable temperature difference. The ground has a much lower temperature than the ambient as the solar radiation cannot penetrate deeply into the soil. Agricultural soil with a different type of plant has been chosen as the source in this study as the different soil composition will provide a different temperature gradient. The temperature gradient was measured from the surrounding and the soil. The highest energy harvested and generated were measured and compared between different types of agricultural soil. The results lead to a finding of a lot of other factors influencing the efficiency of the energy harvesting tools and the voltage generated from different types of soil. It shows that the hot surrounding with colder soil temperature gave a promising result.
